Re: Using unnest function on multi-dimensional array.

Hello

2009/10/12 Nimesh Satam <nimesh(dot)zedo(at)gmail(dot)com>:
> Hi,
>
> Can anybody highlight how to use unnest function from postgres 8.4 on
> multi-dimensional array?
>
> Below is the sample table structure:
>
> Table "public.multi_array_test"
>  Column  |   Type   | Modifiers
> ---------+----------+-----------
>  id      | integer  |
>  user_id | bigint[] |
>
> Sample data:
>
>   1 | {{3567559397,0},{3020933367,1},{2479094216,2},{3310282955,3}}
>
> Regards,
> Nimesh.
>

use generate_subscripts

postgres=#
create or replace function unnest2(anyarray)
returns setof anyelement as $$
select $1[i][j]
from generate_subscripts($1,1) g1(i),
generate_subscripts($1,2) g2(j);
$$ language sql immutable;

postgres=# select * from unnest2(array[[1,2],[3,4]]);
unnest2
---------
1
2
3
4
(4 rows)

regards
Pavel Stehule